I used to have a problem when I updated to the previous beta. I would have to drop back to the offical release and then upgrade again to get the program to work. It would get to 97% and then seem to freeze. In actuality it looked like the program was having trouble loading the textures. I traced it back to some custom skins that I was using for some of the planes. I removed them and then redid the patch (selected the refresh option). That solved the problem for me.